Logistical Concerns for Prehospital Blood Product Use by Air Medical Services

Optimizing the lyophilization of Lumbricus terrestris erythrocruorin

Haemorrhagic shock is a leading cause of death worldwide. Blood transfusions can be used to treat patients suffering severe blood loss but donated red blood cells (RBCs) have several limitations that limit their availability and use. To solve the problems associated with donated RBCs, several acellular haemoglobin-based oxygen carriers (HBOCs) have been developed to restore the most important function of blood: oxygen transport. One promising HBOC is the naturally extracellular haemoglobin (i.e. erythrocruorin) of Lumbricus terrestris (LtEc). The goal of this study was to maximise the portability of LtEc by lyophilising it and then testing its stability at elevated temperatures. To prevent oxidation, several cryoprotectants were screened to determine the optimum formulation for lyophilisation that could minimise oxidation of the haem iron and maximise recovery. Furthermore, samples were also deoxygenated prior to storage to decrease auto-oxidation, while resuspension in a solution containing ascorbic acid was shown to partially reduce LtEc that had oxidised during storage (e.g. from 42% Fe3+ to 11% Fe3+). Analysis of the oxygen equilibria and size of the resuspended LtEc showed that the lyophilisation, storage, and resuspension processes did not affect the oxygen transport properties or the structure of the LtEc, even after 6 months of storage at 40 °C. Altogether, these efforts have yielded a shelf-stable LtEc powder that can be stored for long periods at high temperatures, but future animal studies will be necessary to prove that the resuspended product is a safe and effective oxygen transporter in vivo.

Prehospital Massive Transfusion for Resuscitation of an Entrapped Patient in a Rural Setting: A Case Report

Resuscitation of injured patients suffering from hemorrhagic shock with blood products in the prehospital environment is becoming more commonplace. However, blood product utilization is typically restricted and can be exhausted in the event of a prolonged entrapment. Delivery of large amounts of blood products to a scene is rare, particularly in rural settings. We present the case of a 26-year-old male who was entrapped in a motor vehicle for 144 min. First responders assessed the entrapped patient to be in hemorrhagic shock from lower extremities injuries. The Helicopter Emergency Medical Services team exhausted their supply of blood products shortly after arrival on scene. The local trauma center's Surgical Emergency Response Team (SERT) was requested to the scene. The preplanned response included seven units of blood components to provide massive transfusion at the point of injury and released directly to field responders by the blood bank. During extrication, the patient was given two units of packed red blood cells by initial responders with three more units of blood components from the SERT supply. During transfer to the hospital, the patient received an additional three units, and four units were transfused on initial trauma resuscitation in the hospital. He was found to have severe lower extremities injuries as the cause of his hemorrhage. The patient survived to hospital discharge. Delivery of large volumes of blood products to an entrapped patient with prolonged extrication time may be a lifesaving intervention. We advocate for integration of blood bank services and on scene physician guided resuscitation for prolonged extrications.

Prehospital Critical Care Blood Product Administration: Quantifying Clinical Benefit

BACKGROUND

Prehospital blood transfusion has been widely practiced in the military and is drawing renewed scrutiny after many years of civilian use.

OBJECTIVE

The objective of this article is to quantify the benefit derived from prehospital transfusion of blood products.

METHODS

Deidentified data were extracted retrospectively from the flight records of a critical care transportation program between April 2018 and January 2020. Patients who were transported before a prehospital blood transfusion protocol were compared with patients after initiation of the blood transfusion protocol. Demographic data, vital signs, laboratory analytics, and other outcome measures were analyzed.

RESULTS

Nine scene transport patients who met the transfusion criteria before a blood transfusion protocol were compared with 11 patients transported after initiation of the protocol. Identical outcome measures were analyzed. Patients who received prehospital blood transfusions had a statistically significantly longer hospital length of stay (16.5 vs 3.7 days, P = .03) and were more often taken directly to the operating room (80% vs 28%, P = .04). No statistically significant difference was identified when comparing mean arterial pressure, heart rate, respiratory rate, hemoglobin, hematocrit, or survival to hospital discharge.

CONCLUSIONS

Trauma patients who received prehospital blood transfusion had a longer hospital length of stay and were more often taken directly to the operating room, but without improvement in survival.

How we built a hospital-based community whole blood program

BACKGROUND

Whole blood (WB) is an attractive product for prehospital treatment of hemorrhagic shock and for initial in-hospital resuscitation of patients likely to require massive transfusion. Neither our regional blood provider nor our hospital blood bank had recent experience collecting or using WB, so we developed a stepwise process to gather experience with WB in clinical practice.

METHODS

When our Transfusion Committee suggested a WB program, we worked with our regional blood provider to collect cold-stored, leukoreduced, low-titer anti-A, and anti-B group O RhD positive WB (low-titer group O WB [LTOWB]) and worked with our city Fire Department to integrate it into prehospital care. This work required planning, development of protocols, writing software for blood bank and electronic medical records, changes in paramedic scope of practice, public information, training of clinicians, and close clinical follow-up.

RESULTS

Between June 2019 and December 2021, we received 2269 units of LTOWB and transfused 2220 units; 24 (1%) were wasted, two were withdrawn, and 23 were in stock at the end of that time. Most (89%) were transfused to trauma patients. Usage has grown from 48 to 120 units/month, covers all 5 Fire Districts in the county, and represents about ¼ of all hospital trauma blood product use.

CONCLUSIONS

Developing a WB program is complex but can be started slowly, including both pre-hospital and hospital elements, and expanded as resources and training progress. The investments of time, effort, and funding involved can potentially improve care, save blood bank and nursing effort, and reduce patient charges.

Blood component use and injury characteristics of acute trauma patients arriving from the scene of injury or as transfers to a large, mature US Level 1 trauma center serving a large, geographically diverse region

BACKGROUND

Advanced trauma care demands the timely availability of hemostatic blood products, posing special challenges for regional systems in geographically diverse areas. We describe acute trauma blood use by transfer status and injury characteristics at a large regional Level 1 trauma center.

STUDY DESIGN AND METHODS

We reviewed Harborview Medical Center (HMC) Trauma Registry, Transfusion Service, and electronic medical records on acute trauma patients for demographics, injury patterns, blood use, and in-hospital mortality, 2011-2019.

RESULTS

Among 47,471 patients (mean age 45.2 ± 23.0 years; 68.3% male; Injury Severity Score 12.6 ± 11.1), 4.7% died and 8547 (18%) received at least one blood component through HMC. Firearms injuries were the most often transfused (690/2596, 26.6%) and the most urgently (39.9% ≥3 units in <1 h; 40.6% ≥5 units in <4 h), and had the highest mortality (case-fatality, 12.2%) (all p < .001). From-scene patients were younger than transfers (42.9 ± 21.0 vs. 47.2 ± 24.4), predominated among firearms injuries (68.2% from-scene vs. 31.8% transfers), were more likely to receive blood (18.5% vs. 17.6%) more urgently (≥3 units first hour, 24.4% vs. 7.7%; ≥5 units first 4 h: 25.6% vs. 8.2%), were more likely to die of hemorrhage (15.5% vs. 4.3%) and from firearms injuries (310/1360, 22.8%) (all p < .001).

DISCUSSION

Early blood use, firearms injuries, and mortality were all greater among from-scene patients, and firearms injuries had worse outcomes despite greater and more urgent blood use, but the role of survivor bias for transfer patients must be clarified. Future research must identify strategies for providing local hemostatic transfusion support, particularly for firearms injuries.

Hemostatic Resuscitation of Pediatric Trauma Patients During Air Medical Transport: A Retrospective Matched Cohort Study

OBJECTIVE

The objective of this study was to examine an academic air ambulance service's experience with prehospital transfusion of plasma and red blood cells in pediatric trauma for evidence of efficacy on the treatment of shock and coagulopathy.

METHODS

All trauma patients < 18 years old transfused during transport by the University of Washington Airlift Northwest (Airlift) air medical transport service to Harborview Medical Center, Seattle, WA, were identified. Controls were matched 1:1 from pediatric trauma patients transported by Airlift before transfusion support became available. Demographics, injury scores, emergency department admission and interval laboratory values, blood product use, and hospital outcome measures were registered.

RESULTS

Seventeen cases met the inclusion criteria and were matched by age and Injury Severity Score to 17 control patients (mean age = 10.5 vs. 10.9 years; New Injury Severity Score, 37 vs. 40.7). No significant differences in vital signs, shock index, or mortality were observed. Cases received less in-flight crystalloid (4.3 mL/kg vs. 16.9 mL/kg, P = .004), had higher admission fibrinogen levels (238 vs. 148mg/dL, P = .007), and shorter time to normalization of the international normalized ratio (6.4 vs. 19.1 hours, P = .04).

CONCLUSIONS

In this small series, hemostatic resuscitation during air medical transport was associated with less crystalloid administration and better support of coagulation indices.

Prehospital coagulation measurement by a portable blood analyzer in a helicopter emergency medical service (HEMS)

In helicopter emergency medical services, HEMS, coagulopathy presents both in trauma (e.g. consumption of coagulation factors) and non-trauma cases (e.g. anticoagulant use). Therefore, in HEMS coagulation measurements appear promising and Prothrombin Time (PT) and derived INR are attractive variables herein. We tested the feasibility of prehospital PT/INR coagulation measurements in HEMS. This study was performed at the Dutch HEMS, using a portable blood analyzer (i-Stat®1, Abbott). PT/INR measurements were performed on (hemodiluted) author's blood, and both trauma- and non-trauma HEMS patients. Device-related benefits of the i-Stat PT/INR system were portability, speed and ease of handling. Limitations included a rather narrow operational temperature range (16-30 °C). PT/INR measurements (n = 15) were performed on hemodiluted blood, and both trauma and non-trauma patients. The PT/INR results confirmed effects of hemodilution and anticoagulation, however, most measurement results were in the normal INR-range (0.9-1.2). We conclude that prehospital PT/INR measurements, although with limitations, are feasible in HEMS operations.

The Israel Defense Forces experience with freeze-dried plasma for the resuscitation of traumatized pediatric patients

BACKGROUND

With the growing recognition of the disadvantages of crystalloid- and colloid-based resuscitation and the advantages of using blood products as the preferred resuscitation fluid, the Israel Defense Forces Medical Corps (IDF-MC) adopted plasma as the primary volume resuscitation regimen in 2013. While data are accumulating for prehospital plasma transfusion, little to no data exist regarding using plasma as a prehospital resuscitation fluid for traumatized pediatric patients.

METHODS

All patients treated by the IDF-MC personnel are recorded in the IDF Trauma Registry, a unique prehospital trauma registry. All patients treated by the IDF advanced life support providers with FDP at the point of injury between April 2013 and June 2018 who were younger than 18 years at the time of injury were included.

RESULTS

Six hundred seventy-nine children were treated by IDF medical providers, of whom 33 (5%) were identified in the IDF Trauma Registry as having received FDP at the point of injury. Most patients (80%) were treated for penetrating injuries. Most patients received one plasma unit. Fifty-four percent of the patients were also treated by Tranexamic Acid (TXA) and 48% were transfused with crystalloids. In 33% of patients, additional life-saving interventions were performed.

CONCLUSION

While the ideal resuscitation fluid for the pediatric population remains to be determined, it seems reasonable to pursue a similar approach to that of applied that for adults. In the IDF-MC, the resuscitation fluid of choice for trauma patients in hemorrhagic shock is freeze-dried plasma transfused at the point of injury. The current study demonstrates the feasibility of FDP administration in the prehospital scenario for injured children and further supports the growing confidence in the use of FDP for the treatment of pediatric trauma patients.

LEVEL OF EVIDENCE

Retrospective descriptive study, level IV.

Pre-hospital transfusion of red blood cells. Part 1: A scoping review of current practice and transfusion triggers

OBJECTIVES

The primary aim of this scoping review is to describe the current use of pre-hospital transfusion of red blood cells (PHTRBC) and to evaluate criteria used to initiate PHTRBC. The effects on patients' outcomes will be reviewed in Part 2.

BACKGROUND

Haemorrhage is a preventable cause of death in trauma patients, and transfusion of red blood cells is increasingly used by Emergency Medical Services (EMS) for damage control resuscitation. However, there are no guidelines and little consensus on when to initiate PHTRBC.

METHODS

PubMed and Web of Science were searched through January 2019; 71 articles were included.

RESULTS

Transfusion triggers vary widely and involve vital signs, clinical signs of poor tissue perfusion, point of care measurements and pre-hospital ultrasound imaging. In particular, hypotension (most often defined as systolic blood pressure ≤ 90 mmHg), tachycardia (most often defined as heart rate ≥ 120/min), clinical signs of poor perfusion (eg, prolonged capillary refill time or changes in mental status) and injury type (ie, penetrating wounds) are common pre-hospital transfusion triggers.

CONCLUSIONS

PHTRBC is increasingly used by Emergency Medical Services, but guidelines on when to initiate transfusion are lacking. We identified the most commonly used transfusion criteria, and these findings may provide the basis for consensus-based pre-hospital transfusion protocols.

Pre-hospital transfusion of red blood cells. Part 2: A systematic review of treatment effects on outcomes

The primary aim of this systematic review is to describe the effects of prehospital transfusion of red blood cells (PHTRBC) on patient outcomes. Damage control resuscitation attempts to prevent death through haemorrhage in trauma patients. In this context, transfusion of red blood cells is increasingly used by emergency medical services (EMS). However, evidence on the effects on outcomes is scarce. PubMed and Web of Science were searched through January 2019; 55 articles were included. No randomised controlled studies were identified. While several observational studies suggest an increased survival after PHTRBC, consistent evidence for beneficial effects of PHTRBC on survival was not found. PHTRBC appears to improve haemodynamic parameters, but there is no evidence that shock on arrival to hospital is averted, nor of an association with trauma induced coagulopathy or with length of stay in hospitals or intensive care units. In conclusion, PHTRBC is increasingly used by EMS, but there is no strong evidence for effects of PHTRBC on mortality. Further research with study designs that allow causal inferences is required for more conclusive evidence. The combination of PHTRBC with plasma, as well as the use of individualised transfusion criteria, may potentially show more benefits and should be thoroughly investigated in the future. The review was registered at Prospero (CRD42018084658).

Thinking Out of the (Big) Box: A Wearable Near-Infrared Spectroscopy Monitor for the Helicopter Emergency Medical Service

OBJECTIVE

In prehospital helicopter emergency medical service (HEMS) settings, the medical team has limited monitoring options, usually restricted to systemic variables. Regional tissue oxygenation (rO₂) can be assessed by near-infrared spectroscopy (NIRS), but clinical NIRS monitors are unpractical ("big boxes" and additional cables) in HEMS. As an alternative, we identified a wearable, athlete training NIRS device (Moxy; Idiag, Fehraltorf, Switzerland) and hypothesized that it would be applicable in our HEMS setting.

METHODS

This feasibility study was performed at the Dutch HEMS Lifeliner 1. The Moxy sensor was tested in-flight and on ground. We tested various anatomic measurement spots, and multiple conditions and interventions were imposed to track rO₂.

RESULTS

The rO₂ measurements with the wearable Moxy NIRS device are both feasible and practical in an HEMS setting. Multiple conditions and interventions were tested successfully (eg, tourniquet placement [rO₂↓], muscle compression [rO₂↓], reperfusion [rO₂↑], oxygen administration [rO₂↑], hyperemia [rO₂↑], and venous congestion [rO₂↓]).

CONCLUSION

Our results suggest that rO₂ measurements with the wearable Moxy NIRS device are both feasible and practical in HEMS, and Moxy allows the tracking of simulated pathophysiologic effects on rO₂. Future studies will have to verify our preliminary data and elucidate if and how wearable NIRS monitoring may support treatment in HEMS and improve patient outcome.

Portable Blood (Gas) Analyzer in a Helicopter Emergency Medical Service

INTRODUCTION

In prehospital helicopter emergency medical services (HEMS), the medical team frequently manages critical patients with only limited, noninvasive monitoring options on-site and during HEMS transport. To gain deeper insight into the patient's pathology and to track prehospital treatment effects, a point-of-care blood (gas) analyzer appears desirable also in HEMS. Thus, we hypothesized that prehospital blood (gas) analysis is feasible in the HEMS setting.

METHODS

A prehospital evaluation of a portable blood (gas) analyzer (i-Stat 1; Abbott, Chicago, IL) with appropriate laboratory cartridges was performed within the Dutch HEMS Lifeliner 1, serving a region of ∼4.5 million inhabitants. Venous blood (gas) measurements were performed in our HEMS collective in both trauma and nontrauma cases.

RESULTS

The HEMS team identified benefits (eg, portability and speed) and limitations (eg, a narrow operational temperature range) regarding the tested blood (gas) analyzer. Regarding the actual blood (gas) results, the team collected results without major abnormalities but also cases identifying major pathologies, including several cases of marked acidosis, refractory hypoglycemia, or severe anemia.

CONCLUSION

In conclusion, portable blood (gas) analysis proved feasible in an HEMS operation but with relevant limitations. Future studies will have to show how these limitations can be overcome and how the implementation of portable blood (gas) analyzers may support improved patient outcome.

Is prehospital blood transfusion effective and safe in haemorrhagic trauma patients? A systematic review and meta-analysis

BACKGROUND

Life-threatening haemorrhage accounts for 40% mortality in trauma patients worldwide. After bleeding control is achieved, circulating volume must be restored. Early in-hospital transfusion of blood components is already proven effective, but the scientific proof for the effectiveness of prehospital blood-component transfusion (PHBT) in trauma patients is still unclear.

OBJECTIVE

To systematically review the evidence for effectiveness and safety of PHBT to haemorrhagic trauma patients.

METHODS

CINAHL, Cochrane, EMBASE, and Pubmed were searched in the period from 1988 until August 1, 2018. Meta-analysis was performed for matched trauma patients receiving PHBT with the primary outcomes 24-hour mortality and long-term mortality. Secondary outcome measure was adverse events as a result of PHBT.

RESULTS

Trauma patients who received PHBT with simultaneous use of packed red blood cells (pRBCs) and plasma showed a statistically significant reduction in long-term mortality (OR = 0.51; 95% CI, 0.36-0.71; P < 0.0001) but no difference in 24-hour mortality (OR = 0.47, 95% CI, 0.17-1.34; P = 0.16). PHBT with individual use of pRBCs showed no difference in long-term mortality (OR = 1.18; 95% CI, 0.93-1.49; P =  0.17) or 24-hour mortality (OR = 0.92; 95% CI, 0.46-1.85; P =  0.82). In a total of 1341 patients who received PHBT, 14 adverse events were reported 1.04%, 95% CI 0.57-1.75%.

CONCLUSIONS

PHBT with simultaneous use of both pRBCs and plasma resulted in a significant reduction in the odds for long-term mortality. However, based on mainly poor quality evidence no hard conclusion can be drawn about a possible survival benefit for haemorrhagic trauma patients receiving PHBT. Overall, PHBT is safe but results of currently ongoing randomised controlled trials have to be awaited to demonstrate a survival benefit.

STUDY TYPE

Systematic review and meta-analysis.

Novel platelet products under development for the treatment of thrombocytopenia or acute hemorrhage

Controlling hemorrhage has been a focus of survival since man recognized that the loss of blood led to death. Papyri from 1600 BCE describe methods for hemorrhage control including; direct pressure, ligature and the use of sutures. Multiple studies have demonstrated the survival advantage of early transfusion of whole blood or red cells and plasma. The added survival impact of early transfusion of platelets was recently reported in a substudy of the prospective Pragmatic, Randomized Optimal Platelet and Plasma Ratios (PROPPR) trial. Early transfusion of platelets demonstrated a statistically significant survival benefit at 24 h and 30 days post-injury. [1] Platelet availability is limited due to the short shelf life (5-7 days) and storage requirements (room temperature with constant agitation). Providing platelets or platelet derived products for prehospital treatment and to rural and some urban hospitals is an unmet medical need. The interest in novel and alternative platelet products has grown over the past decade and the status of novel platelet products is presented herein. Development, approval, and distribution of hemostatically effective approved platelet products for prehospital use and routine stockage in rural and urban centers could significantly increase survival rates in bleeding patients.

Blood on board: The development of a prehospital blood transfusion program in a Canadian helicopter emergency medical service

OBJECTIVE

Prehospital blood transfusion has been adopted by many civilian helicopter emergency medical services agencies, and early outcomes are positive. The Shock Trauma Air Rescue Society operates six bases in Western Canada and started a blood on board process in 2013 in Regina that has expanded to all bases. Two units of O negative packed red blood cells are carried on every mission. We describe the processes and standard work ensuring safe storage, administration, and stewardship of this important resource.

METHODS

The packed red blood cells are stored in an inexpensive, reusable temperature controlled cooler at 1°C-6°C. Close collaboration with local transfusion services and adherence to Canadian transfusion standards contributes to safety and sustainability.

RESULTS

From October 1, 2013 to October 10, 2017, the Shock Trauma Air Rescue Society administered blood to 431 patients. Of this total, 62.9% received blood carried on our aircraft. A total of 463 blood box units were administered, and the majority of patients (69.0%) received both units. Blood used in Calgary, Alberta was 100% traceable, and only 1.2% of total units dispensed was wasted. The vast majority of unused units were returned to circulation.

CONCLUSION

We describe the process to set up and monitor a prehospital blood transfusion program. Our standard work and stewardship processes minimize wastage of blood while keeping it readily available for our critically ill and injured patients.